1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * machine_kexec.c for kexec 4 * 5 * Copyright (C) 2022 Loongson Technology Corporation Limited 6 */ 7 #include <linux/compiler.h> 8 #include <linux/cpu.h> 9 #include <linux/kexec.h> 10 #include <linux/crash_dump.h> 11 #include <linux/delay.h> 12 #include <linux/irq.h> 13 #include <linux/libfdt.h> 14 #include <linux/mm.h> 15 #include <linux/of_fdt.h> 16 #include <linux/reboot.h> 17 #include <linux/sched.h> 18 #include <linux/sched/task_stack.h> 19 20 #include <asm/bootinfo.h> 21 #include <asm/cacheflush.h> 22 #include <asm/page.h> 23 24 /* 0x100000 ~ 0x200000 is safe */ 25 #define KEXEC_CONTROL_CODE TO_CACHE(0x100000UL) 26 #define KEXEC_CMDLINE_ADDR TO_CACHE(0x108000UL) 27 28 static unsigned long reboot_code_buffer; 29 static cpumask_t cpus_in_crash = CPU_MASK_NONE; 30 31 #ifdef CONFIG_SMP 32 static void (*relocated_kexec_smp_wait)(void *); 33 atomic_t kexec_ready_to_reboot = ATOMIC_INIT(0); 34 #endif 35 36 static unsigned long efi_boot; 37 static unsigned long cmdline_ptr; 38 static unsigned long systable_ptr; 39 static unsigned long start_addr; 40 static unsigned long first_ind_entry; 41 42 int machine_kexec_prepare(struct kimage *kimage) 43 { 44 int i; 45 char *bootloader = "kexec"; 46 void *cmdline_ptr = (void *)KEXEC_CMDLINE_ADDR; 47 48 kimage->arch.efi_boot = fw_arg0; 49 kimage->arch.systable_ptr = fw_arg2; 50 51 if (kimage->file_mode == 1) { 52 /* 53 * kimage->cmdline_buf will be released in kexec_file_load, so copy 54 * to the KEXEC_CMDLINE_ADDR safe area. 55 */ 56 memcpy((void *)KEXEC_CMDLINE_ADDR, (void *)kimage->arch.cmdline_ptr, 57 strlen((char *)kimage->arch.cmdline_ptr) + 1); 58 kimage->arch.cmdline_ptr = (unsigned long)KEXEC_CMDLINE_ADDR; 59 } else { 60 /* Find the command line */ 61 for (i = 0; i < kimage->nr_segments; i++) { 62 if (!strncmp(bootloader, (char __user *)kimage->segment[i].buf, strlen(bootloader))) { 63 if (!copy_from_user(cmdline_ptr, kimage->segment[i].buf, COMMAND_LINE_SIZE)) 64 kimage->arch.cmdline_ptr = (unsigned long)cmdline_ptr; 65 break; 66 } 67 } 68 69 if (!kimage->arch.cmdline_ptr) { 70 pr_err("Command line not included in the provided image\n"); 71 return -EINVAL; 72 } 73 } 74 75 /* kexec/kdump need a safe page to save reboot_code_buffer */ 76 kimage->control_code_page = virt_to_page((void *)KEXEC_CONTROL_CODE); 77 78 reboot_code_buffer = (unsigned long)page_address(kimage->control_code_page); 79 memcpy((void *)reboot_code_buffer, relocate_new_kernel, relocate_new_kernel_size); 80 81 #ifdef CONFIG_SMP 82 /* All secondary cpus now may jump to kexec_smp_wait cycle */ 83 relocated_kexec_smp_wait = reboot_code_buffer + (void *)(kexec_smp_wait - relocate_new_kernel); 84 #endif 85 86 return 0; 87 } 88 89 void machine_kexec_cleanup(struct kimage *kimage) 90 { 91 } 92 93 void kexec_reboot(void) 94 { 95 do_kexec_t do_kexec = NULL; 96 97 /* 98 * We know we were online, and there will be no incoming IPIs at 99 * this point. Mark online again before rebooting so that the crash 100 * analysis tool will see us correctly. 101 */ 102 set_cpu_online(smp_processor_id(), true); 103 104 /* Ensure remote CPUs observe that we're online before rebooting. */ 105 smp_mb__after_atomic(); 106 107 /* 108 * Make sure we get correct instructions written by the 109 * machine_kexec_prepare() CPU. 110 */ 111 __asm__ __volatile__ ("\tibar 0\n"::); 112 113 #ifdef CONFIG_SMP 114 /* All secondary cpus go to kexec_smp_wait */ 115 if (smp_processor_id() > 0) { 116 relocated_kexec_smp_wait(NULL); 117 BUG(); 118 } 119 #endif 120 121 do_kexec = (void *)reboot_code_buffer; 122 do_kexec(efi_boot, cmdline_ptr, systable_ptr, start_addr, first_ind_entry); 123 124 BUG(); 125 } 126 127 128 #ifdef CONFIG_SMP 129 static void kexec_shutdown_secondary(void *regs) 130 { 131 int cpu = smp_processor_id(); 132 133 if (!cpu_online(cpu)) 134 return; 135 136 /* We won't be sent IPIs any more. */ 137 set_cpu_online(cpu, false); 138 139 local_irq_disable(); 140 while (!atomic_read(&kexec_ready_to_reboot)) 141 cpu_relax(); 142 143 kexec_reboot(); 144 } 145 146 static void crash_shutdown_secondary(void *passed_regs) 147 { 148 int cpu = smp_processor_id(); 149 struct pt_regs *regs = passed_regs; 150 151 /* 152 * If we are passed registers, use those. Otherwise get the 153 * regs from the last interrupt, which should be correct, as 154 * we are in an interrupt. But if the regs are not there, 155 * pull them from the top of the stack. They are probably 156 * wrong, but we need something to keep from crashing again. 157 */ 158 if (!regs) 159 regs = get_irq_regs(); 160 if (!regs) 161 regs = task_pt_regs(current); 162 163 if (!cpu_online(cpu)) 164 return; 165 166 /* We won't be sent IPIs any more. */ 167 set_cpu_online(cpu, false); 168 169 local_irq_disable(); 170 if (!cpumask_test_cpu(cpu, &cpus_in_crash)) 171 crash_save_cpu(regs, cpu); 172 cpumask_set_cpu(cpu, &cpus_in_crash); 173 174 while (!atomic_read(&kexec_ready_to_reboot)) 175 cpu_relax(); 176 177 kexec_reboot(); 178 } 179 180 void crash_smp_send_stop(void) 181 { 182 unsigned int ncpus; 183 unsigned long timeout; 184 static int cpus_stopped; 185 186 /* 187 * This function can be called twice in panic path, but obviously 188 * we should execute this only once. 189 */ 190 if (cpus_stopped) 191 return; 192 193 cpus_stopped = 1; 194 195 /* Excluding the panic cpu */ 196 ncpus = num_online_cpus() - 1; 197 198 smp_call_function(crash_shutdown_secondary, NULL, 0); 199 smp_wmb(); 200 201 /* 202 * The crash CPU sends an IPI and wait for other CPUs to 203 * respond. Delay of at least 10 seconds. 204 */ 205 timeout = MSEC_PER_SEC * 10; 206 pr_emerg("Sending IPI to other cpus...\n"); 207 while ((cpumask_weight(&cpus_in_crash) < ncpus) && timeout--) { 208 mdelay(1); 209 cpu_relax(); 210 } 211 } 212 #endif /* defined(CONFIG_SMP) */ 213 214 void machine_shutdown(void) 215 { 216 #ifdef CONFIG_SMP 217 int cpu; 218 219 /* All CPUs go to reboot_code_buffer */ 220 for_each_possible_cpu(cpu) 221 if (!cpu_online(cpu)) 222 cpu_device_up(get_cpu_device(cpu)); 223 224 smp_call_function(kexec_shutdown_secondary, NULL, 0); 225 #endif 226 } 227 228 void machine_crash_shutdown(struct pt_regs *regs) 229 { 230 int crashing_cpu; 231 232 local_irq_disable(); 233 234 crashing_cpu = smp_processor_id(); 235 crash_save_cpu(regs, crashing_cpu); 236 237 #ifdef CONFIG_SMP 238 crash_smp_send_stop(); 239 #endif 240 cpumask_set_cpu(crashing_cpu, &cpus_in_crash); 241 242 pr_info("Starting crashdump kernel...\n"); 243 } 244 245 void machine_kexec(struct kimage *image) 246 { 247 unsigned long entry, *ptr; 248 struct kimage_arch *internal = &image->arch; 249 250 efi_boot = internal->efi_boot; 251 cmdline_ptr = internal->cmdline_ptr; 252 systable_ptr = internal->systable_ptr; 253 254 start_addr = (unsigned long)phys_to_virt(image->start); 255 256 first_ind_entry = (image->type == KEXEC_TYPE_DEFAULT) ? 257 (unsigned long)phys_to_virt(image->head & PAGE_MASK) : 0; 258 259 /* 260 * The generic kexec code builds a page list with physical 261 * addresses. they are directly accessible through XKPRANGE 262 * hence the phys_to_virt() call. 263 */ 264 for (ptr = &image->head; (entry = *ptr) && !(entry & IND_DONE); 265 ptr = (entry & IND_INDIRECTION) ? 266 phys_to_virt(entry & PAGE_MASK) : ptr + 1) { 267 if (*ptr & IND_SOURCE || *ptr & IND_INDIRECTION || 268 *ptr & IND_DESTINATION) 269 *ptr = (unsigned long) phys_to_virt(*ptr); 270 } 271 272 /* Mark offline before disabling local irq. */ 273 set_cpu_online(smp_processor_id(), false); 274 275 /* We do not want to be bothered. */ 276 local_irq_disable(); 277 278 pr_notice("EFI boot flag: 0x%lx\n", efi_boot); 279 pr_notice("Command line addr: 0x%lx\n", cmdline_ptr); 280 pr_notice("Command line string: %s\n", (char *)cmdline_ptr); 281 pr_notice("System table addr: 0x%lx\n", systable_ptr); 282 pr_notice("We will call new kernel at 0x%lx\n", start_addr); 283 pr_notice("Bye ...\n"); 284 285 /* Make reboot code buffer available to the boot CPU. */ 286 flush_cache_all(); 287 288 #ifdef CONFIG_SMP 289 atomic_set(&kexec_ready_to_reboot, 1); 290 #endif 291 292 kexec_reboot(); 293 } 294